Hi joe!
To compile for multiple architectures on mac-os-x I use the flags
-arch i386 -arch x86_64
instead of -m32.
This makes it possible to use the driver or nif shared object with both 32- or 64-bit erlang.
To link with other shared libraries you need to add
-L<path> -l<name>
Sometimes it gets a bit more complicated than this, but this should be enough for you?
I sometimes revert to link the the code instead of using shared libraries. Then you
do not have to think about dependencies.
Hope it works
/Tony
On 22 dec 2010, at 20.49, Joe Armstrong wrote:
> How do link shared libraries with nifs?
>> I want to make a few nifs and put them in a shared library.
> The problem is that the my nif library in its turn calls things in
> other shared libraries. And when I load my nif library the other
> referenced shared libraries
> are not loaded.
>> I made a little example to illustrate this:
>> I have a file niftest.c with the following nif
>> extern int other_lib_mult(int, int);
>> static ERL_NIF_TERM mult(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
> {
> int a,b,c;
> enif_get_int(env, argv[0], &a);
> enif_get_int(env, argv[0], &b);
> c = other_lib_mult(a, b);
> return enif_make_int(env, c);
> }
>> I make a shared library called niftest.so
> with this command
>> gcc -m32 -O3 -fPIC -bundle -flat_namespace -undefined suppress
> -fno-common -Wall -o niftest.so niftest.c -I
> /usr/local/lib/erlang/usr/include/
>> Which makes the shared library.
>> other_lib_mult is is lib.c and I make a shared library lib.so with a
> similar command to the above
>> When I try to load niftest.so erlang says
>> {error,{load_failed,"Failed to load NIF library: 'dlopen(./niftest.so,
> 2): Symbol not found: _other_lib_mult\n Referenced from:
> /Users/joe/code/nifs/nif2/niftest.so\n Expected in: flat namespace\n
> in /Users/joe/code/nifs/nif2/niftest.so'"}}
>> This is running on mac os-x.
>> Also do all the shared libraries have to be compiled for 32 bit, or
> can I pick and mix
> with 64 bit code. Without the -m32 flag nothing works and some of the
> shared libraries
> I want to call were compiled as 64 bit.
>> Cheers
>> /Joe
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"Have run Make so many times I dunno what's installed anymore"